Bar lock assembly

ABSTRACT

A locking bar assembly for constraining opposing movable section elements. The assembly includes a pair of strike plates with each having one lug element. Each strike plate is rigidly secured to a respective section element in a manner such that bore through openings formed in each lug may be aligned. A bar lock mechanism is insertable through the bore openings in order to constrain the movable section elements. The locking bar assembly further includes a releasable capturing mechanism which provides for an external attacking force to be transmitted to the strike plates instead of to the bar lock mechanism.

United States Patent 1191 Walters Aug. 6, 1974 1 BAR LOCK ASSEMBLY Primary Examiner-Joseph H. McGlynn 75 I 2 I w. W 9 Assistant Exuminer-R1chard P. Tremblay 1 mentor Russel alters Readmg Pa Attorney, Agent, or Firm-Maleson, Klmmelman & [73] Assignee: BMR Security Products, Reading, Ratner [22] Filed: Aug. 3, 1972 [57] ABSTRACT [21] Appl, No 277,565 A locking bar assembly for constraining opposing movable section elements. The assembly includes a pair of strike plates with each having one lug element. [52] US. Cl 70/104, 16/169, 16/171 Each Strike plate is rigidly secured to a respective [51] hit. C1 E051) 63/00 tion element in a manner Such that bore through [58] Fwld 0f Search 70/1, 57, 91, 101, 102, Openings formed in each lug may be aligned A bar 70/104 16/143 176 lock mechanism is insertable through the bore openings in order to constrain the movable section ele- [56] References C'ted ments. The locking bar assembly further includes a re- UNITED STATES PATENTS leasable capturing mechanism which provides for an 3,231,929 2/l966 Hiltunen et al. l6/l36 x xte nal attacking force to be transmitted to the strike 3,464,241 9/ 1969 Wellekens 70/91 plates instead of to the bar lock mechanism. 3,711,894 l/l973 Walters 70/91 X 18 Claims, 5 Drawing Figures PAIENTEDAUB m 3.827.266

SHEET 1 BF 2 BAR LOCK ASSEMBLY BACKGROUND OF THE INVENTION A. Field of the Invention This invention pertains to the field of locking systems. In particular, this invention relates to the field of bar locks. Still further, this invention pertains to the field of bar locks which transmit attacking forces to structural areas removed from the bar lock mechanism.

B. Prior Art Bar lock assemblies including a pair of strike plates with alignable lugs are known in the art. However, in such prior mechanisms, a lever or other mechanism is often used to attack these mechanisms at the lug interface. In such cases, the attacking forces are transmitted directly to the bar lock mechanism inserted through the lug elements. This direct transmission of stress to the bar lock mechanism results in a system which can not withstand high jimmying forces and consequently, may be opened with relative ease.

Other bar lock assemblies include strike plates with three or more alignable lugs. In such cases, where the strike plates are attached to movable elements to be constrained, no misalignment of the elements can be tolerated. Where the strike plates are slightly mismounted or where the movable elements are misaligned, the bar lock mechanism can not be inserted through the lugs.

In other bar lock assemblies, an odd number (three, five, etc.) of lugs are used. Such prior mechanisms do not permit the strike plates to be cast identically. This type of construction leads to higher manufacturing costs as well as adding to the basic structural complexity of the locking bar assembly.

SUMMARY OF THE INVENTION A locking bar assembly which includes a pair of strike plates having respective lug member formed on each of the strike plates. A bar lock mechanism is insertable through the bores formed within each of the lug members when the bores are aligned in a predetermined direction. Also formed on the strike plates is a mechanism for releasably capturing each of the lug members with the strike plate of the other lug member when the bores are aligned in the predetermined direction.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the bar lock assembly mounted on a pair of movable section elements;

FIG. 2 is a sectional view of the bar lock assembly taken along the section line 2-2 of FIG. 1;

FIG. 3 is a sectional view of the bar lock assembly taken along the section line 3--3 of FIG. 2 showing a locking position in phantom lines;

FIG. 4 is a front view of the bar lock assembly; and,

FIG. 5 is an exploded view of the bar lock mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1, 2 and 3, there is shown bar lock assembly or locking system for constraining opposing movable section elements or door members 12,

14. Each of strike plates l6, 18 are securely mounted on a respective section element 12, 14 in a manner such that upon interface of opposing strike plates 16, 18, bar lock mechanism 20 may be inserted through lug or lug members 28, 30 of each strike plate. This insertion constrains each strike plate 16 or 18 to the other and consequently, restrains elements 12 and 14 from movement with respect to each other. As a consequence of the construction of locking system 10, it will be shown in following paragraphs that this system permits some misalignment between door members 12, 14 in a longitudinal direction as defined by directional arrow 22 where lugs 28 and 30 may not be perfectly aligned one with respect to the other. Additionally, the use of the described two lug system also permits some misalignment between plates 16, 1.8 due to the element 12, 14 warping or plate mismounting while not affecting the locking capabilities of system 10. Further, it will be seen where a torqueing force is interspersed at interface 26 between lug members 28, 30, such force is transferred not only to bar lock mechanism 20 but is resisted by strike plates 16, 18 in. themselves, thus increasing the load factor system 10 can accommodate when externally attacked.

In general, locking system 10 includes a pair of strike plates 16, 18 having lugs 28, 30 formed thereon. Each strike plate l6, 18 is secured to a respective door member 12, 14 in a manner such that lugs 28, 30 can be aligned in substantially a direction defined by arrow 22. Bar lock mechanism is then insertable through aligned lug members 28, 30 in order to maintain constrainment between section elements l2, l4.

Strike plates 16, 18 are substantially formed in an L"shaped configuration having respective lug members 28, 30 formed thereon. Each of strike plates 16, 18 are mounted to respective movable section elements l2, 14 through a plurality of bolts, screws, or some like mechanism represented by openings 32. In this manner, strike plates 16, 18 are securely mounted to a respective element 12, 14. Plates 16, 18 are mated or interface with each other that lugs 28 and 30 are aligned in a predetermined direction substantially defined by the orientation of arrow 22. When lugs 28 and 30 are so oriented, bore openings 34 and 36 are in themselves aligned each with respect to the other. Each of the lugs 28, 30 forms a base element of plates 16, 18 and is formed in one piece construction with the vertically directed frame 31 of the respective plate.

Each of strike plates l6, 18 are releasably secured to each other through not only insertion of mechanism 20 but also through releasable capturing mechanisms 38, 40. As shown in FIG. 4, this combined element interaction serves to take up or transfer any load stresses incurred at interface 26, from jimmying or other attack procedure, the strike plates 16, 18 instead of the load being directly transmitted to bar lock mechanism 20. Capturing mechanisms 38, 40 include first mating element or tooth 42 which is formed integral with vertical frame plate 31 of each strike plate 16, 18. As is seen, each tooth 42 extends in a lateral. direction with respect to orientation 22 and is insertable within second mating element or channel 44. Channel 44 is formed within each of lug members 28, 30 and extends through a portion of the circumference of each member 28, 30. In this manner, elements 42 interface with second mating elements 44 when bores 34, 36 are aligned in predetermined direction 22 as defined by the bore axes.

Channels 44 include base surfaces 46 having a substantially constant diameter throughout a portion of the lug peripheral boundary. Channel sections 44 also include opposing sidewalls 48a-b which provide a channel depth substantially equal to but slightly greater than the depth of teeth 42. Second mating elements 44 further form a constant diameter channel base surface 46 taken with respect to the bore axis. This constant diameter surface 46 extends throughout a portion of the respective lug 28 or 30 perimeter until channel demarcation line 50 is reached as is shown. Inclined wall 52, beginning at each line 50, forms into vertical frame 31 of each plate 16, 18. Thus, channel 44 depth decreases from line 50 as a function of lateral dimension until wall 52 forms into the vertical leg of the appropriate strike plate 16 or 18. In this manner, it is seen that either of strike plates 16 or 18 are free to rotate with respect to each other through a portion of the total lug circumference when bores 34, 36 are aligned. This freedom of rotation extends to channel demarcation line 50 where teeth 42 then contact inclined wall formation 52. However, it is now clearly seen that although strike plates 16, 18 are free to rotate, they are constrained in the direction 22 as well as in the rotative direction 24.

Where external attack forces are applied at interface 26 through a lever or other mechanism, there is usually applied a torqueing force which tends to move lugs 28 and 30 away from each other in a direction coincident with arrow 22. In such a case, first and second mating elements 42, 44 provide reaction forces when sidewalls 48a-b contact tooth sidewalls 54 and transmit the external attack force to the strike plates 16, 18 and associated lug members 28, 30, thereby substantially alleviating any force stress directly on bar lock mechanism 20. In this manner, reaction forces responsive to external attack torqueing forces, are substantially taken up by structural elements 42, 44 and, therefore, provide additional structural integrity for system 10. Additionally, when a torqueing force is applied at interface 26, tooth elements 42 may be displaced into channel base surfaces 46. Such a displacement still alleviates any direct force applied to bar lock mechanism 20 within bores 34, 36 since a substantial amount of the stress is taken up on the external surfaces of lugs 28, 30.

In order to provide a greater shear area, thereby permitting larger load resistance characteristics, tooth walls 54 and channel sidewalls 48 may be inclined as shown. Inclination of sidewalls provide a greater surface area when walls 48 and 54 contact each other under force displacement conditions. Since the shear stress capable of being absorbed is proportional to the contacting area, an increase in the contacting area results in a direct increase in the load carrying capability of the contacting members.

Bar lock mechanism 20 as shown in FIG. includes a standard cylinder lock 56 having a retractable locking pin 58. Cylinder lock 56 is insertable within through passage 60 of tubular element 62 where locking pin 58 is aligned with and passes through tubular element sidewall opening 64. As is standard, cylinder lock 56 is key actuated to cause extraction and retraction of locking pin 58 in a direction substantially normal to a line defining the axis of cylinder lock 56. In this manner, with cylinder lock 56 inserted within tubular element 62, bar lock mechanism may be inserted within aligned bore openings 34, 36 to rigidly constrain do'or members 12 and 14 each to the other.

Locking pin 58 is insertable into first detent 66 formed in a wall member defined by one of bore openings 34 or 36 within one of lug members 28 or 30. In this manner, bar lock mechanism 20, may be locked by extending locking pin 58 into first detent 66 where bar lock mechanism passes through at least a portion of each of bore openings 34, 36 thereby constraining strike plates l6, 18 each to the other. As is seen, second detent 68 is formed within the wall member defined by one of bore openings 34 or 36 at a predetermined longitudinally directed distance from first detent 66. The separation distance between detents 66 and 68 is substantially equal to the distance necessary for the removal of bar mechanism 20 from one of bore openings 34, 36. In this manner, bar mechanism 20 may be retracted from one of lug members 28 or 30 and be locked to only one of the lug members by extraction of locking pin 58 into second detent 68. Thus, although bar locking mechanism 20 is locked to one of lugs 28 or 30, free movement between movable elements 12 and 14 is attained. In this way, it is seen that bar lock mechanism 20 may be left attached and locked to one of the legs 28 or 30 while permitting complete freedom of movement of members 12 and 14. Where detent 68 is not provided in system 10, locking pin 58 operates in the manner of a spring loaded latch bolt and key 74 unlocks only from detent 66. Opposingly, when detents 66 and 68 are provided, locking pin 58 does not func-.

tion as a spring actuated locking pin but must be actuated by key 74 to lock or unlock from detent 66 to 68 or in reverse order.

Additionally, bar lock mechanism 20 may be movably constrained within bores 34, 36 through set screw 70 passing through a sidewall of one of lug members 28, 30. Screw member 70 threadedly engages lug member sidewall and is movable with respect thereto. Set screw 70 is further insertable within a channel or groove 72 formed within tubular element 62 as shown and passing in a direction substantially coincident with the axis direction of element 62. In this manner, bar lock mechanism 20 may be slidably moved within bores 34, 36 of lugs 28, 30 for a predetermined distance defined by the length of groove 72. This mechanism prevents complete removal of bar lock mechanism 20 from lugs 28, 30 while permitting slideable movement therein.

A feature of locking system 10 is that mating strike plates 16, 18 are almost identical in construction. The only differences being in that first and second detents 66 and 68 as well as set screw 70 are found in only one lug member 28 or 30. In all other aspects regarding construction material and dimensions, both strike plates 16 and 18 are substantially identical. In this manner, the major elements of system 10 may be case or otherwise constructed in mass volume thereby lowering manufacturing costs. Additionally, since overall external dimensions are the same, mating of plates 16, 18 is ensured. In construction, plate members 16, 18 are formed of hardened steel or some like material capable of maintaining structural integrity when subjected to an attacking force.

It is also to be understood that mounting of system 10 to movable section elements 12 and 14 is completely reversible with respect to insertion of bar lock mechanism 20 within bores 34, 36, in other words, system 10 may be turned upside down without loss of operating function. Plates l6, 18 may be mounted to elements 12 and 14 at a height which would make it awkward to insert mechanism 20 from the top. This may occur when plates l6, 118 are mounted near a ceiling or in excess of the height an operator may comfortably complete the locking and unlocking operations. In such cases, the system may be mounted so that mechanism is insertable from the bottom. On the other hand, where system 10 must be mounted to elements 12 and 14 near a floor, all that must be done is to invert plates 16 and 18 and insert mechanism 20 from the top surface. This invention capability provides a versatility of use for sys tem 10 not usually found in other lock mechanisms of this type.

It should further be understood from the preceding description that the use of two lugs 28 and 30 in combination with mechanisms 38 and 40 provide system 10 with a force carrying capability found ony in locks having a number of lugs in excess of two as in this invention. The use of two lugs provides for the solution of the very practical problem of misalignment. The problem may take the form of (1) misalignment between elements 12 and 14; (2) mismounting of system 10 causing misalignment when elements 12 and 14 are brought together, or (3) a combination of element misalignment and mismounting. Where three or more lugs are used in a locking system, it is evident that any misalignment tolerances must be very small since mating of the lock element is a critical factor. In the present invention, where only two lugs 28 and 30 are used, the aforementioned misalignment tolerances may be much greater while still rendering a working locking bar assembly 10.

A further external attack may be made at point X, shown in FIG. 3, by a tool to force tubular member 62 against blocked passage 34 in lug 28. However, the clearance between locking pin 58 and detent 66 is greater than the clearance between the upper surface of tubular element 62 and the blocked section of lug 28 within opening 36. Therefore, no shearing force would be applied to locking pin 58 in detent 66 and no force would be applied on the lug of set screw '70.

A further external attack may be made at point X, shown in FIG. 3, by a tool to force tubular member 62 against blocked passage 34 in lug 28. However, the clearance between locking pin 58 and detent 66 is greater than the clearance between the upper surface of tubular element 62 and the blocked section of lug 28 within opening 34. Therefore, no shearing force would be applied to locking pin 58 in detent 66 and no force would be applied on the lug of set screw 70.

Additionally, it should be noted that tooth elements 42 extend into the plane of interface 26, as shown clearly in FIG. 1. Further, the upper portion of tube element 62 adjacent interface 26 when element 62 passes into both lugs 28 and 30 may be formed of hardened steel. In combination, this provides protection from attack by a saw or other implement being inserted into interface 26 since any cutting force would be stopped by either the hardened steel portion of element 62 and- /or tooth element 42.

What is claimed is:

l. A locking bar assembly comprising a. a pair of strike plates, each of said strike plates having a respective lug member formed thereon;

b. bar lock means insertable through bores formed within each of said lug members when said bores are aligned in a predetermined direction;

(3. each said lug member having an upper surface, a

5 lower surface and an outer side surface, said upper and lower surfaces formed transverse of said bore within said lug member, said outer side surface having at least one larger diameter section and at least one smaller diameter section, said outer side 10 surface formed between said upper and lower surfaces;

d. at least one first mating means formed by at least one of said strike plates; and,

e. at least one second mating means formed on and I5 shorter than an outer side surface of at least one of said lug members, said first mating means of one of strike plates and said second mating means of said lug member of the other of said strike plates being received one in the other when said bores are 20 aligned in said predetermined direction.

25 means passing through at least a portion of each of said bores for constraining said strike plates each to the other.

3. The bar lock as recited in claim 2 including a second detent formed in said wall member for insertion of 30 said locking pin of said bar lock means, said second detent being positionally located to permit said locking pin insertion when said bar lock means extends through only one of said bores.

4. The bar lock as recited in claim 1 including means for movably restraining said bar lock means within one of said bores formed within one of said lugs.

5. The locking bar assembly of claim 1 in which said first and second mating means together comprise a tooth and groove combination.

6. The locking bar assembly of claim 5 in which said groove extends over a substantial portion of the periphery of an outer side surface of said lug.

'7. A locking bar assembly comprising a. a pair of strike plates, each of said strike plates having a respective lug member;

b. bar lock means received through bores formed within each of said lug members when said bores are aligned;

c. each said lug member having an upper surface, lower surface and an outer side surface, said upper and lower surfaces formed transverse of said bore within said lug member, said outer side surface having at least one larger diameter section and at least one smaller diameter section, said outer side surface formed between said upper and lower surfaces; and,

d. at least one of said strike plates and an outer side surface of at least one of said lug members having mutual mating means, at least one tooth on one and an accommodating groove on the other of said mutual mating means 8. The locking bar assembly of claim 7 in which said groove extends throughout a predetermined portion of 5 the periphery of an outer side surface of said lug mem her.

9. The locking bar assembly of claim 7 in which each said tooth and accommodating groove has inclined walls one with the other for increasing shear reaction force contact areas.

10. The locking bar assembly of claim 7 in which each of said strike plates has only a single respective lug member formed thereon.

11. The locking bar assembly of claim 10 in which each of said strike plates has only a single tooth and each of said lug members has only a single groove.

12. A locking bar assembly comprising a. a pair of strike plates, each of said strike plates having a respective lug member formed thereon;

b. bar lock means insertable through bores formed within each of said lug members when said bores are aligned in a predetermined direction; and,

. means for releasably capturing each of said lug members with the strike plate of the other of said lug members comprising first mating means including a tooth element formed by each of said strike plates and second mating means formed by each of said lug members, said tooth element of one of said strike plates being insertable within a corresponding one of said second mating means formed by said lug means of the other of said strike plates when said bores are aligned in a predetermined direction whereby said first and second mating means provide. reaction forces responsive to and substantially resist torgueing force applied to an interface between said lug members, said reaction forces being substantially formed external said bar lock means.

13. The locking bar assembly as recited in claim 12 where each of said second mating means includes means for permitting rotation of one of said strike plates with respect to the other of said strike plates when said first means is inserted within said second mating means.

14. The locking bar assembly as recited in claim 13 where said second mating means includes a channel formed within each of said lugs for insertion of each of said tooth elements, each of said channels extending throughout a predetermined portion of the periphery of each of said lugs.

15. The locking bar assembly as recited in claim 14 where each of said tooth elements and said channels include inclined sidewalls for increasing shear reaction force contact areas.

16. A locking bar comprising a. a pair of strike plates, each of said strike plates having a respective lug member formed thereon;

b. bar lock means insertable through bores formed within each of said lug members when said bores are aligned in a predetermined direction;

0. at least one first mating means formed by at least one of said strike plates;

(1. at last one second mating means formed on and shorter than an outer side of at least one of said lug members, said first mating means of one of strike plates and said second mating means of said lug member of the other of said strike plates being received one in the other when said bores are aligned in said predetermined direction; and,

e. said first mating means including at least one tooth element received within an accommodateing second mating means for restraining motion between said strike plates in said predetermined direction whereby said first and second mating means substantially resist a torqueing force applied to an interface between said lug members when said bores are aligned in said predetermined direction.

17. The locking bar assembly of claim 16 in which said second mating means includes a channel formed in a sidewall of at least one of said lugs adapted for receiving therein said tooth element of said first mating means.

18. The locking bar assembly of claim 17 in which each of said strike plates has only a single respective lug member formed thereon; each of said strike plates has only a single tooth element and each of said lug members has only a single channel.

0- UNITED STATES PATENT OFFIQE CERTIFICATE OF CORELCTION Patent No. 3 ,2 Dated August 6 197 Inventor) Russell W. Walters It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

a I l Claim 7, line 7 after "surface," insert --a--.

Claim l6,line 10, after "sidefinsert --sur'face--.

Signed and sealed this 8th day of October 1974.

(SEAL) Attest: I

McCOY M. GIBSON JR. C. MARSHALL DANN Attesting Officer Commissioner of Patents 

1. A locking bar assembly comprising a. a pair of strike plates, each of said strike plates having a respective lug member formed thereon; b. bar lock means insertable through bores formed within each of said lug members when said bores are aligned in a predetermined direction; c. each said lug member having an upper surface, a lower surface and an outer side surface, said upper and lower surfaces formed transverse of said bore within said lug member, said outer side surface having at least one larger diameter section and at least one smaller diameter section, said outer side surface formed between said upper and lower surfaces; d. at least one first mating means formed by at least one of said strike plates; and, e. at least one second mating means formed on and shorter than an outer side surface of at least one of said lug members, said first mating means of one of strike plates and said second mating means of said lug member of the other of said strike plates being received one in the other when said bores are aligned in said predetermined direction.
 2. The bar lock assembly as recited in claim 1 where said bar lock means includes a locking pin insertable into a first detent formed in a wall member defined by one of said bores of one of said lugs, said bar lock means passing through at least a portion of each of said bores for constraining said strike plates each to the other.
 3. The bar lock as recited in claim 2 including a second detent formed in said wall member for insertion of said locking pin of said bar lock means, said second detent being positionally located to permit said locking pin insertion when said bar lock means extends through only one of said bores.
 4. The bar lock as recited in claim 1 including means for movably restraining said bar lock means within one of said bores formed within one of said lugs.
 5. The locking bar assembly of claim 1 in which said first and second mating means together comprise a tooth and groove combination.
 6. The locking bar assembly of claim 5 in which said groove extends over a substantial portion of the periphery of an outer side surface of said lug.
 7. A locking bar assembly comprising a. a pair of strike plates, each of said strike plates having a respective lug member; b. bar lock means received through bores formed within each of said lug members when said bores are aligned; c. each said lug member having an upper surface, lower surface and an outer side surface, said upper and lower surfaces formed transverse of said bore within said lug member, said outer side surface having at least one larger diameter section and at least one smaller diameter section, said outer side surface formed between said upper and lower surfaces; and, d. at least one of said strike plates and an outer side surface of at least one of said lug members having mutual mating means, at least one tooth on one and an accommodating groove on the other of said mutual mating means.
 8. The locking bar assembly of claim 7 in which said groove extends throughout a predetermined portion of the periphery of an outer side surface of said lug member.
 9. The locking bar assembly of claim 7 in which each said tooth and accommodating groove has inclined walls one with the other for increasing shear reaction force contact areas.
 10. The locking bar assembly of claim 7 in which each of said strike plates has only a single respective lug member formed thereon.
 11. The locking bar assembly of claim 10 in which each of said strike plates has only a single tooth and each of said lug members has only a single groove.
 12. A locking bar assembly comprising a. a pair of strike plates, each of said strike plates having a respective lug member formed thereon; b. bar lock means insertable through bores formed within each of said lug members when said bores are aligned in a predetermined direction; and, c. means for releasably capturing each of said lug members with the strike plate of the other of said lug members comprising first mating means including a tooth element formed by each of said strike plates and second mating means formed by each of said lug members, said tooth element of one of said strike plates being insertable within a corresponding one of said second mating means formed by said lug means of the other of said strike plates when said bores are aligned in a predetermined direction whereby said first and second mating means provide reaction forces responsive to and substantially resist torgueing force applied to an interface between said lug members, said reaction forces being substantially formed external said bar lock means.
 13. The locking bar assembly as recited in claim 12 where each of said second mating means includes means for permitting rotation of one of said strike plates with respect to the other of said strike plates when said first means is inserted within said second mating means.
 14. The locking bar assembly as recited in claim 13 where said second mating means includes a channel formed within each of said lugs for insertion of each of said tooth elements, each of said channels extending throughout a predetermined portion of the periphery of each of said lugs.
 15. The locking bar assembly as recited in claim 14 where each of said tooth elements and said channels include inclined sidewalls for increasing shear reaction force contact areas.
 16. A locking bar comprising a. a pair of strike plates, each of said strike plates having a respective lug member formed thereon; b. bar lock means insertable through bores formed within each of said lug members when said bores are aligned in a predetermined direction; c. at least one first mating means formed by at least one of said strike plates; d. at last one second mating means formed on and shorter than an outer side of at least one of said lug members, said first mating means of one of strike plates and said second mating means of said lug member of the other of said strike plates being received one in the other when said bores are aligned in said predetermined direction; and, e. said first mating means including at least one tooth element received within an accommodateing second mating means for restraining Motion between said strike plates in said predetermined direction whereby said first and second mating means substantially resist a torqueing force applied to an interface between said lug members when said bores are aligned in said predetermined direction.
 17. The locking bar assembly of claim 16 in which said second mating means includes a channel formed in a sidewall of at least one of said lugs adapted for receiving therein said tooth element of said first mating means.
 18. The locking bar assembly of claim 17 in which each of said strike plates has only a single respective lug member formed thereon; each of said strike plates has only a single tooth element and each of said lug members has only a single channel. 